Chief Executive Fiona Weir told the Daily Post: “Ultimately, the responsibility for paying child maintenance rests with the non-resident parent, but the Child Support Agency has to do its job too in collecting debts and enforcing payment.”

Clwyd West Assembly member Darren Millar was shocked by the amount of money owed in his constituency.

“I'm astonished the arrears are so high,” he said.

“Both parents have a responsibility to support their children when family life breaks down and the CSA is there to ensure this responsibility is not shirked.”

Vale of Clwyd MP Chris Ruane was equally concerned.

He said: “It is shocking nearly £5.5m is owed in arrears in the Vale of Clwyd.

“Unfortunately I know from the cases that come into my office that there are some systematic problems within the collection of child support and this certainly needs addressing.”

“However, it should be noted that CSA arrears have actually been falling recently.

“Regrettably some parents go to great lengths to avoid their financial responsibility to their children, requiring costly and time-consuming enforcement action to be taken against them. But we do not give up on cases and nor do we write off accumulated arrears.”